The letter, written by the Partnership for Civil Justice Fund, and dated Nov. 10, said there was no probable cause to arrest the protesters and that they were escorted to the bridge by police before being suddenly detained.

"The entrapment/trap-and-arrest Brooklyn Bridge mass protest sweep was unlawful and unconstitutional in its entirety," the letter states. "The police may not truncate peaceful First Amendment-protected activity, surround a group, issue no audible orders, prohibit persons from having an avenue of exit, and then arrest the hundreds of persons caught in the trap."

The protesters were arrested during the march after some demonstrators strayed off a pedestrian walkway and started to walk on the roadway.

Protesters said police allowed them on the roadway and then corralled and arrested them.

“We are writing District Attorney Cyrus Vance requesting that his office undertake an appropriate review and dismiss these charges. Those who were illegally swept off the streets should not be subjected to the further injustice of prosecution” said Mara Verheyden-Hilliard, Executive Director of the PCJF in a statement.

DNAinfo is New York's leading neighborhood news source. We deliver up-to-the-minute reports on entertainment, education, politics, crime, sports, and dining. Our award-winning journalists find the stories - big or small - that matter most to New Yorkers.